Daytime flight symbology display system

ABSTRACT

A miniature daytime dynamic alphanumeric/graphic flight symbology generator and display system in which raw aircraft data, such as altitude, airspeed, heading etc., are generated by a display generator into symbology indicating the data intensity. The symbology is transmitted by a signal transmission means, to a symbology image source by a means such as fiber optic links in case of optical signals or flexible cable in case of electrical signals. The symbology from the image source is projected onto a combiner directly in the line of sight of the aviator so that symbology indicating the various conditions of the aircraft is viewed by the aviator as an overlay with the actual scene. The combiner is enlarged to provide a 30° field of view and has a spectral coating thereon to enhance the symbology for daytime viewing. The display generator has a variable control means to increase the data intensity for daytime viewing.

The invention described herein may be manufactured, used, and licensedby the U.S. Government for governmental purposes without the payment ofany royalties thereon.

BACKGROUND OF INVENTION

The present invention is in the field of generating aircraft conditionsymbology for military aviators heads up displays (HUDs). At thepresent, a U.S. Army HUD symbology generator exists for night timesymbology display. However, there is also a need that daytime capablesymbology be displayed in the direct line of sight of an aviator.

SUMMARY OF THE INVENTION

The present invention answers that need by providing a miniature daytimeflight symbology generator system in which raw aircraft data isdynamically displayed in the direct line of sight of the aviator asdaylight readable symbology. Three modifications in the night-timesymbology generator provide a workable daytime symbology generatorsystem. One of these modifications is a means for increasing the outputsignal levels generated in a display generator from the raw aircraftdata inputs. The raw aircraft data may be information such as attitude,airspeed, heading, torque, fuel levels, etc. The increased output signallevels will in turn generate dynamic symbology that is increased inintensity accordingly. The symbology is transmitted to a symbology imagesource by a signal transmission means, such as a coherent fiber opticbundle for optical signals from the display generator of flexible cablefor electrical signals. The symbology image source may be a miniaturecathode ray tube (CRT), a liquid crystal or light emitting diodedisplay. A current day system uses simply a lamp which projects througha reticle static pattern from the combiner into the eye. It does nothave a dynamic alphanumeric or graphic capability. The electro-opticalprovides the enhanced dynamic alphanumeric and graph capabilities.

Two modifications are made in a beam combiner positioned in the line ofsight of the aviator. First, the combiner housing and combiner mirrorare increased in size to provide the necessary field of view for daytimeuse. With the enlarged combiner positioned at a 45° angle with respectto the output beam inpinging thereon from the symbology image source andto the eye of the aviator the necessary 30° field of view is provided.The combiner is also provided with a spectral coating to enhancedaylight viewing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an in line schematic diagram of the present symbologygenerator system; and

FIG. 2 illustrates a helmet heads up display means for the symbologygenerator system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Refer not to FIG. 1 for an explanation of the present daytime flightsymbology generator system which produces aircraft condition symbologywith high enough luminance and spectral characteristics for a daytimeheads up display. The aircraft raw data 10, such as mentioned hereinabove, is applied as various inputs to a display generator 20. Generator20 generates symbology for each of the aircraft data and has outputsignals therefrom representing each set of data. The signals from 20 maybe optical or electrical which are supplied to a symbology image sourceby a signal transmission means 24. Means 24 may be a coherent fiberoptics bundle in the case of optical output signals or a flexibleelectrical cable in the case of electrical output signals. Source 28 ischosen according to the type signals from 20 but may be a cathode raytube if the signals from 20 are electrical signals. Alternatively, 28may be liquid crystal display (LCD), light emitting diode (LED), electroflorescent (EL) or vacuum florescent (VFD). Any of these displays arealigned with the output end of the coherent fiber optics to project theimage of optical signals 30 through focussing optics 33 and reflect offa partially reflecting mirror 35, known in the art as a combiner, intothe line of sight of an aviator's eye 37. Optics 33 and combiner 35 maybe rigidly held in a combiner housing 32. Generator 20 preferably has avariable output signal control means for selectively increasing theintensity of the output signal during daytime operation and decreasingduring nighttime operation.

FIG. 2 illustrates one embodiment of the present system as mounted on ahelmet sight assembly 40. It is noted that the display generator 20 andinputs 10 thereto are not shown but may be mounted on the same helmet(not shown either) upon which assembly 40 is attached. In thisembodiment, source 28 is in the form of a reticle projector 46,Projector 46 may be screw threadably attached to 40 through a mount 52.Projector 46 is shown as having two types of signal inputs. One input isby fiber optics 42 and the other is by electrical cable 44, either orboth which may be used. In this instance, the explanation will assume anoptical input into 46 from the output end of 42. The output end of 42will be imaged on a reticle pattern within 46. Projector 46 may have adisplay that projects the fiber optical output image and recticlepattern through focussing optics 50 as beam 46A onto combiner 35 fordisplay thereon directly in the line of sight of the aviator. Thecombiner housing 32 is attached to one end of combiner arm 48 with theother end of arm 48 held by a friction clip 49. The pilot can easily seethe overlay of the symbology from 46 on combiner 35 in his direct lineof sight.

As mentioned above the housing 32 and combiner mirror 35 are of suchsize as to present a 30° field of view, which is generally 50% largerthan what is required for night vision observance. Housing 32 is easilyadjustable to the level of the aviator's eye 37 by movement of arm 48through friction clip 49 and then releasing clip 49 to lock 48 in place.Arm 48 is also rotatable to the side of the head in a stow positionabout a stem 51 connected to 46. There may be one set of 35 and 46 foreach eye. Alternatively, the projector 46 may also be side mounted withthe combiner 35 and arm 48 rotatable to the forehead stow position.

I claim:
 1. A miniature dynamic alphanumeric and graphic flightsymbology generator system for use in a heads up helmet mounted displaydaytime environment, said system comprising:a display generator havingvarious inputs thereto from raw aircraft data and internal signalgenerating means providing various output signals therefrom in directrelationship to the aircraft data and variable signal control means toincrease the value of said output signals during the daytime to providedaytime observance of the symbology generated; a symbology image sourcewhich has a luminance in direct relation to said output signals appliedas inputs thereto through a signal transmission means from said displaygenerator to said symbology image source; and a beam combiner meanspositioned in the line of sight of at least one eye of an aviator, saidbeam combiner means comprised of focussing optics and a mirrorpositioned at an angle to reflect the display on said symbology imagesource directly back into the eye of the pilot wherein said mirror has aspectral coating thereon for enhancing the image for daytime viewing. 2.The system as set forth in claim 1 wherein said symbology image sourceis a miniature cathode ray tube and said signal transmission means is aflexible cable interfacing with said display generator.
 3. The system asset forth in claim 1 wherein said signal transmission means is acoherent fiber optic bundle for transmitting optical signals from saiddisplay generator to a display within said image source wherein saidoptical signal is projected by a reticle projector onto said combinermeans.